Shares jumped as much as 25% Thursday after the fuel-cell company reported double-digit revenue growth in the fourth quarter. The firm reported its bookings reached $32 million, thanks to strong product sales and maintenance orders from large companies such as Wal-Mart Stores Inc., Kroger Co. and BMW.

The company also reported a $62.7 million net loss for 2013, continuing a streak of unprofitable years stretching back to the founding of the company, but investors seemed instead to focus on the revenue growth–and the optimistic tone the company sounded for the rest of 2014.

Chief Executive Andy Marsh said Plug Power started the first quarter by signing a multisite, multiyear contract for its new GenKey product with Wal-Mart that exceeded the company’s goals for the period. “I firmly believe that this continuing momentum will carry on throughout 2014, and that orders for this year will total more than $150 million–almost four times our total for 2013,” Mr. Marsh said.

The good news comes after a tough few days for Plug. Shares plunged 42% on Tuesday following a scathing report from research firm Citron Research, which dismissed the company’s fundamentals and said Plug has become a “casino stock” on Wall Street. From Citron:

“A casino stock, by contrast, is the lowest form of speculative moonshot. A casino stock can trade twice its outstanding shares in a single day, while turning over its entire float on people gambling that they can find a buyer at a higher price … Who really cares about anything else, right? The recent volume and share price surge in Plug Power (NASDAQ:PLUG) demonstrates how Wall Street treats this stock: nothing more than a casino.

“Who is behind PLUG, and what do they do? This is simple: Plug Power sells fuel cell-powered forklifts … with fuel cells they acquire from Ballard Power. Nothing fancy here, folks. Same business model since the 2000 crash … Well over a decade as a public company, during which they have lost close to $850 million, while developing no IP or meaningful revenue growth. Profitability? Forget about it!”

Plug operates in the sector that make technologies focused on fuel cells, which through a chemical reaction convert hydrogen or gas to produce electricity to power forklifts, generators and vehicles, among other things. The sector has a long history of unprofitability and is known for its volatile share moves and heavy short-interest positions.

That hasn’t stopped traders recently from piling in.

Plug’s volume has skyrocketed since the start of the year, putting it among the most actively traded stocks in the U.S. In the past 30 days, it has seen 49 million shares change hands daily, on average, more than any stock in the S&P 500 except Bank of America Corp., Facebook Inc. and Verizon Communications Inc., according to FactSet.

On Thursday, more than 93 million shares traded as of 12:45 p.m. Eastern Time–a number made all the more remarkable by the fact that the company only has about 105 million share outstanding.

“This is a speculative play, without a doubt,” said Ian Winer, director of equity trading at Wedbush Securities Inc., which doesn’t publish analyst research on Plug. “We’re in a wild bull market and watching a stock like Plug shows that the retail investor is coming back.”

He said the fact that Plug can “turn over its float multiple times in a week…is indicative of a large day-trading presence.”

Plug’s stock has been on a wild ride over the past year. It traded as low as 15 cents last April and remained under $1 as recently as early December. But as the chart below shows, the stock surged 338% this year through Wednesday’s close. It traded as high as $11.41 on Monday.

Plug Power shares over the past year

FactSet

But the recent moves pale in comparison to what transpired during the tech boom.

Seasoned day traders remember Plug vividly from the late 1990s and early 2000s, when fuel-cell stocks were all the rage. Plug skyrocketed in its first four-and-a-half months of a trading as a public company and peaked at $1,510, yes $1,510, in March 2000 before suffering a precipitous drop.

Plug Power shares since the October 1999 IPO

FactSet

While it’s tempting to think of Plug as simply the latest day-trader’s plaything, the company sold $22.4 million worth of stock to a “single institutional investor” earlier this month, suggesting there’s at least one large, well-capitalized investor who’s willing to look past the $540 million in net losses Plug has racked up over the past decade. It’s possible that holder will disclose the position in the coming weeks.

Recently, Plug’s largest shareholder was Heights Capital Management Inc., according to FactSet. Quant hedge funds like Renaissance Technologies LLC and Two Sigma Investments LLC were also among its major holders.

Notably absent among the highest ranks of its owners are the typically buy-and-hold-oriented large mutual fund firms like Fidelity Investments or T. Rowe Price Group Inc., which appear near the top of the holder list in many U.S. stocks. This holder data relies on regulatory filings from asset-management firms that don’t provide an up-to-the-minute snapshot, so that may have changed recently.